【django】カテゴリーモデルから選択肢を作成する方法 (models.ForeignKey)

class Category(models.Model):
    lang_type = models.CharField(max_length=50)

    def __str__(self):
        return self.lang_type

    class Meta:
            db_table = 'categories'

# 先にカテゴリーを定義
class Category(models.Model):
    lang_type = models.CharField(max_length=50)
    # ...

class Blog(models.Model):
    title = models.CharField(max_length=200)
    content = models.TextField(blank=True)
    # 下記の行を編集
    category = models.ForeignKey(Category, on_delete=models.SET_NULL, blank=True, null=True)
    updated_at = models.DateTimeField(auto_now=True)
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.title

    class Meta:
        db_table = 'blogs'

from django.contrib import admin

from .models import Blog, Contact, Category

admin.site.register(Blog)
admin.site.register(Contact)
admin.site.register(Category)

python manage.py makemigrations blog
python manage.py migrate

python manage.py runserver